HELP - Daikin Configuration WD curve and modulation with a Madoka room thermostat

Hardware Heatpump
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Hi, please excuse the tirade of posts and I hope this is appropriate and in the right section/forum, I have a Daikin 8kW EDLA08E2V3 installed by Octopus, we are really happy with the install with a full re-pipe mostly 28mm, down to 22mm with 15mm radiator connections, 80% new radiators (K2’s and K3’s) with a design temp of 45, the only gripe is the lack of configuration from Octopus of the MMI and the Daikin User Guide is awful.

The house has been really comfortable with a room temp set to 20 (24/7 schedule) and 18 upstairs, downstairs is basically open loop (with TADO open, but the living room would turn down if we had the log burner on) and upstairs I use TADO TRV’s to maintain temps.

I have just successfully set up the ESPAltherma, thanks to the community for the help and pointers.

Now I can monitor the COP while appreciating the inaccuracy of the Daikin sensors, at least I have a baseline to make changes and compare.

My COP appears to be amazing well over 4 when I have a WD curve 32 @ 15 and 38 @ -3 and a modulation of 10, but I am seeing power fluctuations and COP variances when the system ticks over past the initial boost.

This morning, I have just changed the modulation to 2 and the COP is even better with a higher flow temp, however the system has now reached the room temp and turned off, I will have to see the cycling effects, however the house was basically almost up to temp as I made the modulation change.

I am keen on a set and forget ECO scenario (good enough, not perfect) - using the Madoka and WD, I would just like to dial it in a little.

My ASK -

Can others share their weather-dependent curve and modulation settings so I can make a few tweaks and see the results?

Many thanks Neil

PS we have a 200-year-old 4 bed Semi-detached house with a 10-year-old extension and an EPC rating of A (internal wall insulation in the old part of the house).

Yesterday’s Power Draw and flow rates with a modulation of 10, you can see the startup peak and the fluctuating values, I guess to keep the DT of 5?

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I have also used the following as a starting for 10 but noted the comments from a heat geek elite installer about modulation, hence I have just moved to ‘2’.

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I think, I have really smoothed out the power draw (less wear and tear on the heat pump?) and flow temp with the modulation on 2, even though the house is old its well-insulated and the air temp does not fluctuate that much. I guess I just need to compare and tweak the curve with other setups as the COP looks good as it’s an upward trend?

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I guess there are diminishing returns but, maybe I can squeeze a little more efficiency, should I be happy with a mean COP over 4.53 at ~5 degrees C outside temps for DHW and Space Heating?

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This is a great learning exercise, I think there is a lot of scope for Machine Learning here and Daikin could help, I believe Tado implement this paradigm with their controls and legacy Gas boilers?

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Thanks for posting the links, I have a look at them later.

You should be happy with a COP of 4.5 at 5C. I would be. I’m now getting around 4 when my system is running, which is a big improvement on where I was before.

Just thought I’d jump in with some reassurance your performance is looking good :+1:

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thanks for the reply @HydroSam here is my starter for 10 curve, copied from @Stephen_Crown for better or worse :slight_smile: I believe he is set on LWT pure weather compensation without a Madoka.

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My heat pump is identical to yours, somewhat of a self install with an heat pump company supplying the unit, cylinder and doing the commissioning. My system is open loop, bungalow, no additional pumps or low loss headers, all brand new underfloor heating at 150mm centres on 100mm PIR between joists. I have no room temperature reference at all at this stage, I’m planning on controlling comfort with the flow meters on my underfloor heating circuits.

Does modulation work similarly to overshoot? I’m finding overshoot very helpful with my pure weather compensation - my heat pump is currently a little overpowered for my house as we are mid deep renovation and only 2/3 of the heating is installed.

I also flatted my curve right off as you have, my heat pump cycles alot below 32C.

Mine went from short cycling to basically running 24/7 at 7L per minute (this will rise as i add more heating loops as it wont need to run so slow to maintain DT5). As you know I’ve got a power meter on the way but going by the MMI it’s boosted my cop tremendously. The power consumption remained very similar (going by ocotpus smart meter data) but heat output increased massively.

On the MMI it simply reads 1KW every two hours pretty much the entire day, with some 2KW spikes when its interrupted by DHW reheat. The mmi listed heat is now 4 most of the time which could mean 4.5kw who knows - will know more once i finish my metering!

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thanks @jtrent it would be good to get some data from your home assistant setup and logs when you’re up and running; every house is obviously different but together i am sure we can find a sweet spot and share ideas/methods :slight_smile:

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A post was split to a new topic: Performance of 9kW Daikin

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A post was merged into an existing topic: Performance of 9kW Daikin

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@squarepeg77 here is the 8kW thread for optimisation I mentioned in the 9kW thread, also some videos in the original post for Modulation, maybe this could help @matt-drummer

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I am back to a modulation of 8, and the heat cycle last night was longer and a COP of ~5

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Hi Neil,

Thanks for all your help, I watched the videos a few days ago when you first posted them, I think I had seen all of them before but it was useful to watch them again.

I changed my modulation to 8 today, it makes no difference, it was 2.

I may remove it completely tomorrow, I’ll explain, I just need a steady fixed flow temperature, I know 36c will give me a dT of about 6.3c and a COP of 5.0 plus or minus a bit putting out 4,500w of heat at 900w of electrical input. That was the point of all my testing, I know what gets me a COP of 5 at the least electrical input. Now I know that I can just try and find a way of getting as close to it as I can but not running 24 hours a day as I was.

My problems are twofold, my heat pump produces too much heat for the house, today I need 2kW of heat but the heat pump produces 4 to 4.5kW.

So I can only run it for 40 to 50% of the day, that is now taken care of by the Madoka holding (sort of) 22c room temperature

The other problem is a dip in performance after the first 30 minutes of a heating run, it coincides with the drop in flow rate from 25lpm down to 10lpm, the flow temperature drops, the dT closes and the heat output drops. It recovers after another 30 to 40 minutes and then the COP recovers to 4.50 to 5.00

How to stop the drop in flow temperature?

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@tiger_cook ,

Here is a copy of my MMI Export,

I do currently have a setback scheduled for overnight but particularly in this colder weather it is killing my COP for hours in the morning to come back up even 1°c with defrosting also being a pain.

While my WDC way look odd I also allow for 10°c modulation up and down (usually downwards once the system is running and stable) allowing the Madoka room stat to do its job and keep us warm.
Farnborough,Hampshire-DaikinMMI-export.txt (6.8 KB)

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Thanks @KnightPhoenix our setups look very similar - we have a room temp set of 20 and modulation of 8 + 38 and 30 degree WDC, but a schedule of 24/7. here is my MMI Export.

98k_MMI_Export.txt (7.1 KB)

I have just tried limiting the pump to 60% the results are not apples for apples as the room temp was not 19.5 degrees at the start but around 20.5 (I will check again tonight and update) but I have noticed –

The l/min dropped from 27 to 16 l/min (as per the configuration limitation), then settled to the normal 7 l/min,
The DT was greater for longer, then settled,
the peak power draw was ~500W lower and ran for less time, I am sure this is because of the higher room temp starting point,
but the HP did not stop heating for 20 mins, trying to lose the heat from the loop…then startup again to settle
and I think the room heat up curve was lower, with a similar mean COP at 1 degree outside temps

unlimited pump-

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60% pump limit-

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I may look to drop ours further however we are currently waiting 4 more radiator swaps and I want to avoid a cold lounge (or further upsetting my very patient OH).

Interesting that it takes that long to stabilise after heating but a few people have noticed the 30-45 min spike on startup so maybe that would help.

Only thing I am a little wary of is limiting the pump speed as surely it would be better to have a higher flow and reduce the temperature further and allow modulation to push it up if needed?

Could the issue here be that on startup the pump aims for WDC until it has time to calculate return water temperature and see how much heat is lost before it starts to modulate (down or up)?. May explain some of the spikes on some systems.

Happy to be wrong (and who knows how and why Diakin seems to work this way) but I think a lot of this is going to be trial and error as even the installer reference guide is not great or clear at times.

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agreed, I understand flow is king, but the data contradicts this?
I try to change one thing and see the results….

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Just an update, I am on a 70% pump limit, its been tricky to see a trend and change with -4 outside temps, the power demand peak appears to be the same as unlimited, but the delta T during startup is a little higher 5-7 ( 7-9 with 60%) rather than 3-5 on unlimited, the result is a lower heat up time and I think a greater COP.
I will leave it for a few days as its due to heat up over the next few days and my aim is to have a longer and slower heat up cycle during milder outside temps increasing the COP, rather than the DT narrowing and stopping the HP then starting up again ~20 mins later after the system tries to lose the heat then initiates a second heat up and peak of electricity before settling in to a steady state.

Its really odd as all my research infers you must have a high flow rate to lower the LWT, maybe in my situation, we have little resistance as a result of a full re-pipe 28 – 22 – 15 with oversized radiators, I will follow the data and take advice from others :wink:

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Eventually you will reach a lwt that cannot give the dT required and then a higher flow rate is necessary to get the heat.

If the radiators can maintain a requested dT at a low flow temperature and need a low flow rate to do it then that is great…Generally I would expect that most homes won’t get a high dT at really low flow temperatures and therefore need a higher flow rate to get the heat.

As an example you could flow 10lpm at a dT of 8c or 20lpm at a dT of 4c, the heat produced would be the same, one way may use more electricity than the other due to pump speed and flow temperature required.

Just experiment until you find the best outcome.

You may find that tighter dT at a higher flow rate uses less electricity as the water comes back to the heat pump closer to the lwt but maybe not as it needs to heat more of it by less.

My own approach is the lowest possible flow temperature at the biggest dT and lowest flow rate, should produce the most heat for the least electricity. Less flow temperature also seems to minimise defrosts.

There is no one correct answer, heat produced is just a product of the loss of temperature of how much water. There is more than one way to get the same result.

Every home will be different and how low you can go depends on many factors.

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Thanks @matt-drummer thanks for your help,

I have gone back to an unlimited pump setting last night, I think it’s best for us to just let the HP do its thing, I did note the LWT was higher when throttled so I guess using more energy, also the heat up times look slower with an unlimited pump setting., at was our main goal

I think the Daikin algorithm (modulation) needs to influence and change the pump speed quicker depending on the outside temps so it does not overshoot the targeted room temp, again I am chasing diminishing returns, our space heating COP was over 3.5 at -4 outside, and a cop over 4.5 when around 2 outside at our off peak electric rate of 7p per unit it’s all good.

BTW have Daikin returned to tweak or dial in for settings?

last 48hr, 24hr with 70% pump limit then 24hr unlimited.

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Hi Neil,

Daikin will not be coming to tweak any settings on my heat pump, there are no big enough tweaks available!

My heat loss at -4c is around 4.5kW

The 9kW is going and will be replaced with an 8kW soon.

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Hi @tiger_cook and @matt-drummer interesting discussion on configuration. I have a new Daikin 8kW EDLA08E2V3 installed by Octopus - same as Neil and just now trying to optimise the efficiency. Interesting links to videos although I don’t seem to have anywhere near as many controls on my MMI as the one in the video. Just noting that @tiger_cook said in the original post that he’d set up the ESPAltherma to monitor COP - just wondering what this was as I would really like to be able to monitor this and make adjustments?